Apparatus for the automatic control of blowers for the controlled ventilation of heat exchangers

ABSTRACT

Apparatus for automatically controlling ventilators of heat exchangers, especially for ventilating condensers of an air conditioning plant with two heat exchangers having each a blower with a temperature controlled changeover switch (11) in the current supply line for the blower motors (8, 9) for shifting the blower motors from series to parallel operation when a selectable temperature is exceeded.

United States Patent Illg 51 Feb. 1, 1972 [54] APPARATUS FOR THE AUTOMATIC [56] Reterences Cited CONTROL OF BLOWERS FOR THE I CONTROLLED VENTILATION O UNITED STATES PATENTS HEAT EXCHANGERS 3,484,671 12/1969 Rinaldo ..318l111 7 3,180,403 4/1965 Breen .....165/127 1 lnvenwn Manfred ills, s m Germany 2,756,026 7/1956 Myrent et a1. ..16S/l27 [73] Assignee: Fir-ma Suddeutsehe Kuhlerfabrik Julius a Fr. Behr, Stuttgart-Feuerbach, Germany Bummer-Charles sukal) Attorney-Robert H. Jacob [22] Filed: Mar. 11, 1970 [21] Appl. No.: 18,527 1 1 ABSTRACT v I o Apparatus for automatically controlling ventilators of heat [30] Foreign Applicafiuupriority Data exchangers, especially for ventilating condensers of an airconditioning plant with two heat exchangers havin'g'each a Mar. 12, Germany u. 3.7 blower a temperature controlled changeover switch l in the current supply line for the blower motors (8, 9) for [52] "165/39165/127' 313/1 shifting the blower motors from series to parallel operation [51] Int. Cl ..B60h l/QO when a selectable temperature is exceeded [58] FieldofSearc ..165/32,39,40, 127;-318/11l 6 Claims, 6 Drawing Figures PATENTED ma H972 a SHEET 1 [IF 5 p In venfor" WWW/P55 MA G PATENTED FEB H972 Sit-338718 sum 2 UF 5 lnvenior WW/Mp 446;

PATENTED FEB 1 I972 SHEET 3 [IF 5 PATENTEU FEB 11972 3 3 318 SHiET k BF 5 Fig. 40

Inventor: W/V/fi[fl MA 6 PATENTEUFEH HHTZ 3.638.718

SHEET 5 or 5 In venior:

APPARATUS FOR THE AUTOMATIC CONTROL OF BLOWERS )R THE CONTROLLED VENTILATION OF HEAT EXCHANGERS BACKGROUND OF THE INVENTION The invention relates to the automatic control of blowers. More in particular, the invention concerns an arrangement for the automatic control of blowers for the controlled ventilation of condensers of an air conditioning plant installed in a vehicle.

The blower motors of heat exchangers must be of especially strong construction to take care of heat increases under critical driving conditions. In known plants the condenser blowers are always operated at full capacity as soon as the vaporizer blower is running. This requires a considerable amount of power from the powerline of a motor vehicle equipped with an air-conditioning plant. On the other hand, however, the full blower capacity is by no means continually required.

It is, therefore, an object of this invention to construct an apparatus of the type mentioned in such a manner that it meets the requirements of the practice better than the apparatuses known heretofore, and particularly to adapt the blower or ventilation performance to the refrigerating capacity with relatively small technical means.

SUMMARY OF THE INVENTION In accordance with the invention this requirement is essentially satisfied with a temperature controlled changeover switch which is installed in the current supply system of the blower motors for shifting the blower motors from series to parallel operation after a selectable temperature is exceeded.

In this manner it is accomplished that the condensers installed in the vehicle are sufficiently cooled for normal operation, but when unfavorable operating conditions occur that subject the condensers to extremely heavy loads, an increase in the heat transfer capacity is immediately and automatically available. This provides the additional advantage of economy in the electrical output of the blower motors of the heat exchangers during normal operation and thereby a decrease in the current supply which is dependent on the vehicle.

In accordance with a further feature of the invention a switch is provided that depends on temperature for cutting in the blower motors as a temperature limit is reached or exceeded.

In an air-conditioning plant where the condensers provided with blowers serve as heat exchangers and a vaporizer with a blower is provided, a magnetic coupling operable by a temperature controlled switch is advantageously provided for cutting in the refrigeration compressor.

In accordance with a further feature of the invention it is possible to arrange a pressostat in the condenser conduit between the condensers and the liquid containers or on the fluid container.

in accordance with a further feature of the invention it is advantageous to disconnect the refrigerating compressor when it is overloaded, and to provide a temperature responsive disconnector for disconnecting the magnetic coupling upon the exceeding an upper limit temperature.

It is especially suitable when the cutover switch and/or the disconnecting switch is mounted on the fluid container, particularly threadedly secured thereto.

In accordance with the invention it is also possible to obtain a longer life of the blower motors as well as a relief of the switches and switch contacts.

BRIEF DESCRIPTION OF THE DRAWINGS Further advantages and features of the invention are explained with reference to the drawings, which illustrate an embodiment of the apparatus in accordance with the invention in which:

FIG. I is a schematic side view of a vehicle equipped with FIG. 3 is an operating diagram of the plant in accordance with the invention, and

FIGS. 40, 4b and 4c show details of the temperature responsive switches.

BRIEF DESCRIPTION OF THE INVENTION The arrangement in accordance with the invention is connected to the electrical circuit of the vehicle by way of a starter relay and a protective device such as a fuse 2.

The starter relay I is connected in such a manner that it opens when the starter is operated.

A three-stage switch 3 serves to cut in the evaporating blower 4. Simultaneously a control thermostat 5 on the evaporator receives current. If refrigeration is required, then the control themiostat 5 operates and thereby the connection with ground 6 is established.

The condenser or condensers is or are coordinated with the condenser blowers 8 and 9. The condenser blower motors 8 and 9 are connected parallel to the electromagnetic coupling 7. In the lead to the blower motor 8 a temperature operated switch 10 is provided which closes at a condenser temperature of approximately 50 C. By way of the cutover switch which may, for example, be a relay having two changeover contacts, also the second condenser motor blower 9 is supplied with current. In the position of the cutover switch 12, which is illustrated in the position without current and which has two changeover contacts, the condenser blower motor 8 is connected in series with the condenser blower motor 9. As a result both blower motors operate at one-half the line potential and a quarter of the power input of the line potential.

Both condensers blower motors then run with 6 v. operating potential, whereby the output is approximately ll w. per motor for an embodiment that has been constructed.

The ventilating at the two condensers is sufficient for carrying off the condenser heat that develops with average driving speeds up to 35 C. of outside temperatures. At velocities from 60 km. upward, it is even more so.

If the condensation temperature increases as a result of higher outside air temperatures or high compressor output at lower driving velocities, or at standstill above 60 C., which would cause the refrigerating output to decrease, the temperature responsive cutover switch ll and cutover switch I2 are pulled up. As a result the condenser blower motor 8 operates at line potential as it now is directly connected to ground. Simultaneously the condenser blower motor 9 also receives line potential directly from the supply line of the plant so that the blower switch is not overloaded.

The two condenser blower motors 8 and 9 are connected in parallel for this circuit condition, and in connection with the embodiment described are operated at 12 v., so that an output of about 45 w. per motor results.

A temperature responsive excess temperature switch 14 shuts off the electromagnetic coupling 7 at approximately 70 C. condenser temperature in order to avoid an overloading of the refrigeration compressor, of the electromagnetic coupling or of the V-belt drive of the vehicle. If the defects or outside influence that may lead to an overload are of temporary nature, then the overload temperature switch 14 again cuts in the plant. The heat diffusion at the two condensers is not interrupted during the period of disconnection of the excess temperature switch 14, because in the circuit in accordance with the invention the two condenser blower motors 8,9 are independent of the excess temperature switch 14 or of the electromagnetic coupling 7. The temperature responsive switch 10 is especially desirable when the refrigerating plant is operated for dehydrating the interior of the vehicle at low outside temperatures.

The current supply to the two condenser blower motors 8 and 9 in series connection is only established as a condenser temperature of 50 C. is obtained.

The temperature responsive switches 10,11 and 14 may suitably be in the form of snap-disk thermostats which are arranged on the outer surface of the fluid container for heat conduction or are threadedly mountedon thisouter wall. In lieu of the temperature responsive switch 14 it is also possible, 'as indicated in the drawing, to utilize a pressostat 13 mounted in the condensate conduit between the condensers and the liquid container.

The arrangement in accordance with the invention and the shifting possibilities of two blower motors in connection with on or several heat exchangers results with small electrical power intake in effective cooling of the corresponding heat exchangers during normal operation and automatically shifts over the blower motors in order to make available the required increased output ofheat transfer capacity under spccial operating conditions. 1

The invention is not limited to the embodiment illustrated and described. It also includes all modifications that are readily near at hand for the man skilled in the art and particularly all partial or subcombinations of the features described and/or illustrated.

I claim: 1

1. Apparatus for the automatic control of blowers for the controlled ventilation of heat exchangers, particularly for ventilating the condensers of an air-conditioning plant in a motor vehicle, said apparatus comprising two heat exchangers, a blower for each heat exchanger, two blower motors, one connected to each blower, a current supply line for each motor, a condenser operated relay connected to one of said motors, a temperature controlled relay .in said supply line having one position connecting said motors in series and another position connecting said motors in parallel, and a temperature responsive cutover switch operatively connected with said temperature controlled relay to change the position thereof as the preselected temperature to which the cutover switch is set changes.

2. Apparatus in accordance with claim 1, where said heat exchangers with blowers serve as condensers of a refrigerating plant, including a three-stage switch and a vaporizing blower operatively connected to said three-stage switch, a magnetic coupling connected in parallel with said motors and a temperature responsive switch for cutting in or starting the refrigeration compressor.

3. Apparatus in accordance with claim 2, including a liquid container and a condensate conduit intermediate condensers associated with said blower motors, and a pressostat in. said condensate conduit.

4. Apparatus in accordance with claim 2, including an excess temperature switch operative upon exceeding an upper temperature limit to disconnect said magnetic coupling.

5. Apparatus in accordance with claim 2, including a liquid container and an excess temperature switch, said changeover switch and said excess temperature switch being mounted in said container.

6. Apparatus in accordance with claim 2, where said temperature controlled relay has two sets of changeover contacts including two contacts each connected to one of said motors. 

1. Apparatus for the automatic control of blowers for the controlled ventilation of heat exchangers, particularly for ventilating the condensers of an air-conditioning plant in a motor vehicle, said apparatus comprising two heat exchangers, a blower for each heat exchanger, two blower motors, one connected to each blower, a current supply line for each motor, a condenser operated relay connected to one of said motors, a temperature controlled relay in said supply line having one position connecting said motors in series and another position connecting said motors in parallel, and a temperature responsive cutover switch operatively connected with said temperature controlled relay to change the position thereof as the preselected temperature to which the cutover switch is set changes.
 2. Apparatus in accordance with claim 1, where said heat exchangers with blowers serve as condensers of a refrigerating plant, including a three-stage switch and a vaporizing blower operatively connected to said three-stage switch, a magnetic coupling connected in parallel with said motors and a temperature responsive switch for cutting in or starting the refrigeration compressor.
 3. Apparatus in accordance with claim 2, including a liquid container and a condensate conduit intermediate condensers associated with said blower motors, and a pressostat in said condensate conduit.
 4. Apparatus in accordance with claim 2, including an excess temperature switch operative upon exceeding an upper temperature limit to disconnect said magnetic coupling.
 5. Apparatus in accordance with claim 2, including a liquid container and an excess temperature switch, said changeover switch and said excess temperature switch being mounted in said container.
 6. Apparatus in accordance with claim 2, where said temperature controlled relay has two sets of changeover contacts including two contacts each connected to one of said motors. 